Decreasing productivity of pine forests on the southern edge of the Mongolian Plateau as indicated by tree rings

Abstract

Vegetation productivity on the southern edge of the Inner Mongolian Plateau, which plays a vital role in the ecological environment and in the arable and pastoral production in this region, can be characterized by the NDVI (normalized difference vegetation index). However, the observed NDVI data span only the last ~ 40 years. The growth of Pinus tabulaeformis Carr. is strongly correlated with the NDVI, making it a valuable proxy for extending the length of observed NDVI datasets. In this study, we reconstructed an NDVI series for 1776–2021 for the Daqing Mountains, based on a tree-ring width chronology. The reconstructed data accounted for 55% of the variance in the observed data, and its statistical characteristics and validation indicate that the reconstruction is dependable. Spatial correlation analysis demonstrated the consistency of climate signals in central Inner Mongolia in both the arable and pastoral zones. The results of superposed epoch analysis revealed a good temporal consistency between drought and flood events and the reconstructed NDVI sequence in this region.